Information on seed-rain composition of plant communities allows predictions concerning the successional development of the community and its recovery potential. In fragmented landscapes, seed rain is highly influenced by the connectivity among the remaining fragments and by vegetation structure. In this study we compared the seed rain of three fragments of Atlantic forest (Caucaia do Alto, SP), taking into account fragment size, connectivity in the landscape, edge/interior condition, vegetation structure, and previous disturbance, to verify how these parameters affected the seed rain. Seeds were classified according to primary dispersal syndrome, species life form, and functional type. Based on species attributes, we tested for possible edge effects (chi-squared). We searched for relationships among fragment features (size, connectivity), seed trap position (edge, interior), and the abundance of each diaspore type through detrended correspondence analysis (DCA) and Spearman correlation test. The majority of the 28,873 seeds belonged to arboreal (80.7%) and zoochoric species (73.7%). Late successional tree species predominated in the "small/isolated" fragment, while the "small/connected" fragment showed opposite characteristics. The "large/source" fragment had the highest species diversity and a well-defined edge. Based on these parameters, patterns point to a better ecological condition in the "small/isolated" fragment, followed by the "large/source", and finally by the "small/connected" fragments. We found a contrast between the effects of connectivity and vegetation structure; the latter was more important than fragment connectivity in determining patterns of life form, functional type and dispersal syndrome of seed-rain species.
Atlantic forest; habitat fragmentation; plant dispersal; seed rain
